In electrical and electronic equipment, not only high performance, miniaturization and cost is required but also design and manufacturing technology suitable for product diversification and shortening of the product cycle. However, generally in fine patterning of a film formed by masking and etching using a photolithography of a metal or non-metallic material thin film, the process becomes complicated, flexibility of the pattern is limited, and It is difficult to form a continuous pattern on a site with large steps, and the etching rate in the case of a non-metallic material is slow, damage is caused to the substrate or device structure and there are many manufacturing problems such as the durability of the mask material caused by an etching gas due to high etching temperatures.
In recent years, a method has been developed in which a raw material such as metal nanoparticle ink or a metal alkoxide solution was dropletized using an inkjet method, directly drawn on a substrate to form a fine pattern, then, by applying a heat treatment or the like, a metal or ceramic film fine structure is formed without performing an etching step. By making the droplets small, a structure with a line width of about 1 μm can be formed.
In this method, it is necessary to crystallize a fine pattern formed on the substrate by a heat treatment because the pattern before a heat treatment is not crystallized or metallized. However, when a heat treatment is performed once after stacking a film, cracks and peeling occur which makes it difficult to stably produce a device due to shrinkage of the film caused by crystallization, and because it is necessary to repeat deposition in the same location every time in order to obtain a film thickness, it is difficult to form a thick film structure at high speed.
In a conventional ink jet method, droplets are spread due to a capillary effect caused by wettability of a substrate material due to surface tension and surface roughness of the substrate when the droplets impact on the substrate, and because line width becomes several times more than the diameter of a droplet, fine drawing becomes even more difficult. In order to overcome this, for example, a fine inkjet technology is described in Japanese Laid Open Patent 2004-165587 in which the nozzle aperture size is miniaturized to 10 μm or less, and by making the size of the discharged liquid droplets 1/1000 or less in volume using electric field absorption, and it is possible to obtain fine drawing with a micron-sized width.
However, in the technology of Japanese Laid Open Patent 2004-165587, because the droplet size is very small, the supply of a material per nozzle onto a substrate becomes an extremely small amount, the film thickness in a single drawing is about several tens of nm, and in order to obtain a thickness of more than a few microns, recoating more than several tens of times is required. Therefore, there were practical problems such that a longer manufacturing time is required and a practical throughput cannot be obtained, and clogging of the nozzle is caused because the nozzle is miniaturized.
However, for example, a technology is described in Japanese Laid Open Patent 2009-101356 in which the time the droplet diameter of fine droplets of ink deposited on a substrate reaches the maximum allowed droplet size is set as the allowable elapsed time, and from the time of impact to when the allowable elapsed time elapses, the fine droplets which have impacted on the substrate are set to a scanning speed for moving to an irradiation position from the impact position, and when the allowable elapsed time elapses from the time of impact, when the fine droplets impacted are located at the irradiation position, the shape of the structure to be formed by irradiating a laser beam is controlled. However, the technology described in Japanese Laid Open Patent 2009-101356, in order to irradiate a laser beam onto fine droplets when they impact a substrate, when the laser heat is insufficient, the droplet is not sufficiently dried or solidified, and when the power of the laser is strong, fine holes or irregularities may be produced that are considered to cause a bumping phenomenon of the ink, optimization of the conditions is difficult, and miniaturization of the structure becomes more difficult.